Environment

Iceberg More Than Five Times the Size of Manhattan Is About to Break Off From Antarctica's Pine Island Glacier

By Drew MacFarlane

October 15 2018 03:00 PM EDT

weather.com

00:33

Pine Island Glacier Could Lose Iceberg 5x Size of Manhattan

Satellite images show a huge iceberg five times the size of Manhattan could soon break away from the Pine Island Glacier.

At a Glance

Scientists have recently discovered a large rift on West Antartica's Pine Island Glacier that could result in a massive iceberg breaking away.

If it were to break off in one piece, the iceberg would measure about 115 square miles, or more than five times the size of Manhattan.

While the soon-to-be iceberg is not yet loose from the ice shelf, it's calving is thought to happen "relatively soon."

Scientists have recently discovered a large rift stretching across West Antarctica's Pine Island Glacier that could cause a massive iceberg more than five times the size of Manhattan to break off, satellite imagery shows.

The split stretches nearly 19 miles long starting from the middle of the Pine Island Glacier and has only six miles to go before one or more icebergs break away from the glacier, Stef Lhermitte, an assistant professor in the Department of Geoscience and Remote Sensing at the Netherland's Delft University of Technology, told Live Science.

The rift's origin is located where the ice shelf comes in contact with warmer ocean waters, causing it to melt from underneath.

Lhermitte receives satellite images of the glacier daily, which he analyzes for any irregularities. On Oct. 3, he spotted the rift.

"It was Wednesday evening and all of a sudden I saw something I didn't see the day before," he said.

If the iceberg were to break off in one piece, its size would qualify it to receive a name. However, even if the rift leads to numerous icebergs breaking off, it will be the sixth large-calving event to happen on the Pine Island Glacier since 2001, Lhermitte tweeted.

Glacial calving is completely natural, but the calving at Pine Island Glacier is happening at an increased frequency which has become concerning.

"What we're witnessing on Pine Island Glacier is worrying," said Dr. Robert Larter of the BAS. "We're now seeing changes in the calving behavior of the ice shelf when for 68 years we saw a pattern of advance and retreat resulting in the calving of a single large iceberg which left the ice front to approximately the same place."

Changes to Antarctic ice mass since 2002, created with NASA and the German Aerospace Center's twin Gravity Recovery and Climate Experiment (GRACE) satellites. Pine Island Glacier is located in the dark-shaded pocket on the left side of the map shown above.

(NASA/German Aerospace Center)

While the soon-to-be iceberg hasn't come loose yet, Lhermitte says that the rift's near completion across the glacier suggests calving "might happen relatively soon," putting a likely timetable from a few weeks to a few months.

Once the calving takes place, the iceberg could either stay frozen if it stays near Antarctic sea ice or melt if it's brought by ocean currents into warmer waters further north.

The reason behind Pine Island Glacier's loss of its ice shelf is difficult to pin down. The warm water that's melting the underside of the ice shelf was brought from the deep ocean.

"The reason why we get this upwelling of warm water is certainly climate related, but it's very difficult to say if this is climate change related," said Lhermitte. "Antarctica is a very sensitive continent for climate change. But for this individual iceberg, this is impossible to infer."

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